SiBE04-101
Checks
Service Diagnosis
121
5.1.4
Power Supply Waveforms Check
Check No.12
Measure the power supply waveform between pins 1 and 3 on the terminal board, and check the waveform
disturbance.
Check to see if the power supply waveform is a sine wave (Fig.1).
Check to see if there is waveform disturbance near the zero cross (sections circled in Fig.2)
5.1.5
Power Transistor Output Check
Check No.13
Measure the output current and voltage of the power transistor.
Output Current
Measurement
Remove the front panel, and measure the current in the red, yellow and blue wire harness inside the
compressor using a clamp meter.
1. Attach the clamp meter to the red, yellow and blue wire harness, and conduct forced cooling operation.
2. When the output frequency has stabilized, measure the output current of each phase.
3. If the current outputs of all the phase are balanced, it is normal.
4. If even one phase is out of balance, replace the outdoor unit PCB (INV PCB).
5. If the compressor stops before the output frequency stabilizes, measure the output voltage.
Output Voltage
Measurement
Remove the front panel, and disconnect the red, yellow and blue wire harness inside the compressor from
the terminals. Measure the output voltage of the red, yellow and blue wires using a tester.
1. Remove the compressor wire harness from the PCB.
2. When the LEDs A and 1 start flickering simultaneously by keep pressing the forced operation switch for
longer than 5 sec., release the switch.
3. If the voltage of AC150V to 200V is outputted between DC-130 and U, DC-130 and V and DC-130 and
W, the PCB is normal.
Check the wire harnesses form the power transistor up to the compressor (for breakage of wire and
erroneous wiring).
4. If the voltage of AC150 to AC200V is not outputted, replace the outdoor PCB (INV P board).
Note:
1. Do not touch the terminals of the red, yellow and blue wires when the power is supplied.
(Touching them is very dangerous since a voltage of over 100V is applied.)
2. Do not short-circuit the terminals of the red, yellow, and blue wires.
[Fig.1]
[Fig.2]
SiBE04-101.book Page 121 Monday, October 15, 2001 3:08 PM
